Amplifier for radiophones



J. J. LOW

AMPLIFIER FOR amloPnouss Filed on. 21. I922 JZ/MJ' Low private as Well Patented Feb. 2, lfif iti.

JOHN J. LOW, 0F SANTA ANA, fiAL-Il UItl llLEh.

AMPLIFIER FUR Ril DIDYHGZQ-LEEL application filed October 21,1922. Serial h e. 593,834.

to supplant the usual head phones. More particularly, my invention apportains to amplifiers of that type including-a pcrma nent magnet and asoicn'oid which cooperate to citcct the vibration of an armature in cansin; the vibration of a diaphragm.

In amplifiers of this charactcr, there are two objections to their success commercially: first, the countercnrrent-s setup in the solenoid because of the magnetic lines of force emanating from the permanent mag not andtraversingthc solenoid winding atfect the armature to the extent of producing that familiar and objectionable roaring sound at the diaphragm which is such ahindrance to the clarity ot the sounds produced. The second objection is the rigid connection between the diaphragm and an mature which functions to cause an early disintegration of the mica diaphragm, and which prevents the control at the volume of sound produced to render it applicable to as public use.

It is a purpose of my invention to provide an amplifier which overcomes the above pointed out objections.

I will describe one form of amplifier embodying my invention and will then point out thenovel features thcreot in claims.

In the accompanying drawings,

Figure l is a view showing: in vertical sec tion one form of amplilier embodying my invention Figure 2 is a plan view of the amplifier ineg ihanism removed from the casing shown in Figure 1;

Figure 3 a view Sl10\\'i!l.-j in side elevation the mechanism shown in Figure 1.;

Figure 4 is a sectional view taken on the line 4;4; of Figure 2;

Figure 5 is a fragmentary enlarged detail perspective View of the pole pieces of the permanent magnet and the adjacent mechanism.

Similar reference characters refer to similar parts in each of the views.

Retort-inn; specifically to the drawings, and. particularly to Figure 1, my invention, in its present cmhodimcnt, comprisss casing or housing 15 constructed at nonmagnetic material. and provided with a cover it at" similar material formed with. an opening adapted to receive an ear pioec 17'; The open till ing of the cover it; receives a diaphragm 18 held in place by the ear piece and 'opera-' tively connected to an. arn'iatnre it? of a solenoid contained Within the casing '15, 'lhe solcnoid includes a wil'idingg 310 support ed on a core 21 of insulating material which is engaged by set screws 22 at, its liar corners for centeri tho armature with respect to thepole pieces of the permanent magnet. 'llho'permancnt magnet indicated at 23 and as shown in Figure l is mounted within the casing If. The pole pieces designated at 24 are constructcd in the manner clearly shown in Figure 5, wherein it will he seen that two north polcs and t o Swill p le are providod.- These poles are disposed in circumferential alinement with tho inner and. outer peripheries of the poi'i'nanent magnet 23 so that the gaps hetwccn the poles ars adapted to receive the opposite ends of tho armatnrc '19 The armature 19 is hilcrumed on pins 25 so as to allow at a rocking; movement of the armature within the core 21. The armature is "toriined ot' a rapidly demagnotiaahlo material and because of its association with the solmoid winding 20 it will be clear that polarities are established in the armature to cooperate With-the polarities of the pole piccesfi l in effecting the vi bration of the armature about the pivot pins 25 as a center. The mode oi operation of an amplifier of this character is Well known in the art.

In the assembly of the solenoid between the ends of the permanent magnets 23, a rectangular casing; 26 ot diamagnetic material is arranged between the pole pieces 24: and in enihracingrelation to the core 521, the screw 3 extending through the casing 26 and engaging the core :tor properly ccntering the latter and, consequently, the armature with relation to the pole pieces of the permanent magnet. The upper screws 22 project through the cover lltl, as clearly shown in Figure v k From the foregoing arrangement of the casing QGancl the fact that it is formed of diamagnetic material, it will be clear that it operates to prevent the passage of the till magnetic. lines of force emanating from the permanent magnet 23 through the turns of the solenoid'winding 20, thereby precluding the generation of counter currents inthe solenoid. The magnetic flux of the solenoid winding 20 is thus free to properly act upon the armature 19 and to cooperate with the flux of the permanent magnet in effecting the proper vibration of the armature. The net result is that the armature acts in such a manner as to effect a vibration of the diaphragm 18 without the usual roaring sound so common in similar amplifiers heretofore proposed.

The armature 19 is operatively connected with the diaphragm ISthrongh the medium of a. lever 27 having one end bent at an angle to provide an extension 28 which is connect.- ed to the center of the diaphragm through the medium of a screw 29. The opposite end of the lever 27 is connected to a link '30 which, in turn, is connected to an extension 31 of the inner'cnd of the armature 19. The lever 27 is supported for rocking movement by means of a cross arm 32 formed integral with the lever an-d'provided with grooves adapted to receive the edges of blades secured in projections 34 forming a part of the cover 16. The cross arm 32 is urged in the direction of the blades 33 by means of springs 85 mounted on the shanks of screws 36 threadedly engaging the projections 34 so as to be capable of adjustment for bearing the pressure exerted by the springs.

fill

In practice, the lever 27 under the "ibratory' action of the armature 19 oscillates about the edges of the b1ades 33 as a center, and because of the small bearing surface be tween the cross arm 32 and the blades 33, it

' will be evident that-the lever 27 is extremely scnsitircto the movement of the armature in transmitting such movement to the diaphragm i8. y

To'controlrthe eohune' of soundmroduced the diaphin. 18 so as toren-der the amplifier applicab e to private as well as public use, the oscillatory movement of the lever 27 can be readily controlled by an adjust ment of the screws 36 to increase or decrease the urgin action of the springs 35 with regard to t e cross arm For example, .if

arness it is desired to" modulate the sounds cmanating from the diaphragm 18, the screws 36 are screwed inwardly with respect to the projections 34 to compress the springs 35 so as to oppose movement of the cross arm 32, thereby providing a substantially rigid connection between the armature and the diapl'iragm.

I claim as my lllVCTltlOll-Z 1. An amplifier oi": the character describcd,

comprising a source otmagnetism of constant flux dens ty, a second source of magnetism of varying flex density, an armature operable by the sources of magnetism, a casing prevcntlng the 4 scribed, a permanent magnet having' polc pieces arranged in pairs with the *pole pieces of one air spaced from the pole pieces of the oti er pair, an electro magnet arranged between the two pairs of le pieces, an armature pivotally sustaine on the ,electro-magnet and operating between the pole pieces, and a casing of diamagnetic material surrounding'the electro-magnet be tween the pairs of pole pieces for the purpose described.

3. In an amplifier of the character described, a permanent magnet having pole pieces arranged in pairs with the pole pieces of one pair spaced from thepole pieces of the other pair, an electro-magnet arranged between the two pairs of pole pieces, an armature pivotally sustained on the electrosecond source of magnetism,

magnet. and operating between the pole pieces, a casing of diamagnctic material surrounding the electro-magnet between the pairs of pole pieces for the purpose described, and means carried by the casing for centering the armature with relation to the pole pieces.

In testimony whereof I have signed my name to this specification.

JOE-LN, J'. LOW. 

